In Vitro Micropropagation of Industrially and Medicinally Useful Plant Aloe trichosantha Berger Using Offshoot Cuttings.

This study was aimed to develop in vitro micropropagation protocol of Aloe trichosantha Berger using offshoots as explants. MS media supplemented with plant growth regulators helped explants develop shoots within about 14 to 17 days. The mean number of days to shooting has decreased from 16.8 ± 0.8 with 0.5/0.5 mg/L BAP/NAA supplement to 15.5 ± 0.5 with 2.0/0.5 mg/L BAP/NAA. While the mean shoot number has increased with increasing the concentration of BAP supplements, the reverse was true with mean shoot lengths, whereas supplement of 2.0/0.5 mg/L BAP/NAA has generated significantly more shoots (17 ± 3.8), and longer shoots were produced with the addition of 0.5/0.5 and 1.0/0.5 mg/L BAP/NAA. In regard to rooting, though higher concentrations of NAA have resulted in quick rooting, the rooting performance in terms of mean number and length of roots was better with low concentrations. All the plantlets subjected to greenhouse acclimatization in cocopeat have survived. Secondary acclimatization in composted and manured soil media has also resulted in 93 to 95% survival rate. Lighting conditions (nursery shade or direct sunlight) of secondary acclimatization did not lead to any difference in the survival rate of the plantlets.

In Vitro Micropropagation of Aloe adigratana Reynolds Using Offshoot Cuttings.

This study aimed at developing a suitable and reproducible protocol for in vitro micropropagation of Aloe adigratana Reynolds using explants from offshoots with the help of the most commonly used plant growth regulators (PGRs). Explants were initiated in full-strength Murashige and Skoog (MS) media enriched with 0.2 mg/L benzylaminopurine (BAP) + 0.2 mg/L naphthaleneacetic acid (NAA). Shooting experiment was conducted in full-strength MS media enriched with 0/0, 0.5/0.5, 1.0/0.5, 1.5/0.5, and 2.0/0.5 mg/L BAP/NAA. Likewise, rooting experiment was carried out in half-strength MS media enriched with NAA at 0.5, 1.0, and 1.5 mg/L and indol-3-butyric acid (IBA) at 0.5, 1.0, and 1.5 mg/L. Finally, acclimatization study was conducted in greenhouse, nursery, and open field. The shooting response of the plant was best in MS media enriched with 1.0 mg/L BAP + 0.5 mg/L NAA. This media formulation resulted in the shortest mean number of days to shooting (14.00 ± 2.30 days), the highest mean shoot number (4.00 ± 3.40), and the second highest mean shoot length (8.60 ± 2.10 cm). IBA enhanced rooting at higher concentrations (1.0 and 1.5 mg/L), but NAA did the same at lower concentrations (0.5 and 1.0 mg/L). All plantlets (n = 62) survived primary acclimatization. Secondary acclimatization in composted and matured soil media under nursery and open field (sun light) condition produced 88 to 93% survival rate. The death of plantlets in the secondary acclimatization is accounted to mechanical damage. This study demonstrated that the tested PGRs were useful in enhancing the in vitro micropropagation of the plant. Future studies need to focus on optimizing the protocol for large-scale, commercial micropropagation.

Determination of four salicylic acids in aloe by in vivo solid phase microextraction coupling with liquid chromatography-photodiode array detection.

In recent years, great concerns have been raised about salicylic acid (SA) and its derivatives as plant regulators. Therefore, precise determination of the distribution of SAs in the living plants is necessary for not only fundamental researches but also the regulating mechanisms. In this study, a custom-made solid phase microextraction (SPME) fiber based on diallyl dimethyl ammonium chloride-assembled graphene oxide-coated C18 composite (C18@GO@PDDA) was proposed for in vivo detection of salicylic acid, acetylsalicylic acid (ASA), 4-methyl salicylic acid（4-SA）and 3-methyl salicylic acid (3-SA) in aloe plants. Under the optimized conditions, the analytical performance evaluated in homogenized aloe plant tissues exhibited low detection limits (1.8-2.8 µg g-1), wide linear ranges (10-5000 µg g-1), and satisfactory reproducibility (relative standard deviations less than 8.4% and 9.3% for inter-fiber and intra-fiber assays, respectively). Under cadmium stress, the developed method was applied for the in vivo tracing of four salicylic acids in aloe plants. A 48-h in vivo tracing revealed that salicylic acids were involved in the pathway of cadmium stress tolerance. To our best knowledge, it is the first effort to realize the in vivo analysis of SA and its derivatives in plants, and it has a made a great step forward in the area of plant hormone analysis.

Effects of water stress and light intensity on chlorophyll fluorescence parameters and pigments of Aloe vera L.

Aloe vera L. is one of the most important medicinal plants in the world. In order to determine the effects of light intensity and water deficit stress on chlorophyll (Chl) fluorescence and pigments of A. vera, a split-plot in time experiment was laid out in a randomized complete block design with four replications in a research greenhouse. The factorial combination of three light intensities (50, 75 and 100% of sunlight) and four irrigation regimes (irrigation after depleting 20, 40, 60 and 80% of soil water content) were considered as main factors. Sampling time was considered as sub factor. The first, second and third samplings were performed 90, 180 and 270 days after imposing the treatments, respectively. The results demonstrated that the highest light intensity and the severe water stress decreased maximum fluorescence (Fm), variable fluorescence (Fv)/Fm, quantum yield of PSII photochemistry (ФPSII), Chl and photochemical quenching (qP) but increased non-photochemical quenching (NPQ), minimum fluorescence (F0) and Anthocyanin (Anth). Additionally, the highest Fm, Fv/Fm, ФPSII and qP and the lowest NPQ and F0 were observed when 50% of sunlight was blocked and irrigation was done after 40% soil water depletion. Irradiance of full sunlight and water deficit stress let to the photoinhibition of photosynthesis, as indicated by a reduced quantum yield of PSII, ФPSII, and qP, as well as higher NPQ. Thus, chlorophyll florescence measurements provide valuable physiological data. Close to half of total solar radiation and irrigation after depleting 40% of soil water content were selected as the most efficient treatments.

Mineral content and biochemical variables of Aloe vera L. under salt stress.

Despite the proven economic importance of Aloe vera, studies of saline stress and its effects on the biochemistry and mineral content in tissues of this plant are scarce. The objective of this study was to grow Aloe under NaCl stress of 0, 30, 60, 90 and 120 mM and compare: (1) proline, total protein, and enzyme phosphoenolpyruvate carboxylase (PEP-case) in chlorenchyma and parenchyma tissues, and (2) ion content (Na, K, Ca, Mg, Cl, Fe, P. N, Zn, B, Mn, and Cu) in roots, stems, leaves and sprouts. Proline and PEP-case increased as salinity increased in both parenchyma and chlorenchyma, while total protein increased in parenchyma and decreased in chlorenchyma, although at similar salt concentrations total protein was always higher in chlorenchyma. As salinity increased Na and Cl ions increased in roots, stems, leaves, while K decreased only significantly in sprouts. Salinity increases typically caused mineral content in tissue to decrease, or not change significantly. In roots, as salinity increased Mg decreased, while all other minerals failed to show a specific trend. In stems, the mineral concentrations that changed were Fe and P which increased with salinity while Cu decreased. In leaves, Mg, Mn, N, and B decreased with salinity, while Cu increased. In sprouts, the minerals that decreased with increasing salinity were Mg, Mn, and Cu. Zinc did not exhibit a trend in any of the tissues. The increase in protein, proline and PEP-case activity, as well as the absorption and accumulation of cations under moderate NaCl stress caused osmotic adjustment which kept the plant healthy. These results suggest that Aloe may be a viable crop for soil irrigated with hard water or affected by salinity at least at concentrations used in the present study.

Blow me down: a new perspective on Aloe dichotoma mortality from windthrow.

BACKGROUND: Windthrow, the uprooting of trees during storms associated with strong winds, is a well-established cause of mortality in temperate regions of the world, often with large ecological consequences. However, this phenomenon has received little attention within arid regions and is not well documented in southern Africa. Slow rates of post-disturbance recovery and projected increases in extreme weather events in arid areas mean that windthrow could be more common and have bigger impacts on these ecosystems in the future. This is of concern due to slow rates of post-disturbance recovery in arid systems and projected increases in extreme weather events in these areas. This study investigated the spatial pattern, magnitude and likely causes of windthrown mortality in relation to other forms of mortality in Aloe dichotoma, an iconic arid-adapted arborescent succulent and southern Africa climate change indicator species. RESULTS: We found that windthrown mortality was greatest within the equatorward summer rainfall zone (SRZ) of its distribution (mean = 31%, n = 11), and was derived almost exclusively from the larger adult age class. A logistic modelling exercise indicated that windthrown mortality was strongly associated with greater amounts of warm season (summer) rainfall in the SRZ, higher wind speeds, and leptosols. A statistically significant interaction term between higher summer rainfall and wind speeds further increased the odds of being windthrown. While these results would benefit from improvements in the resolution of wind and substrate data, they do support the hypothesised mechanism for windthrow in A. dichotoma. This involves powerful storm gusts associated with either the current or subsequent rainfall event, heavy convective rainfall, and an associated increase in soil malleability. Shallow rooting depths in gravel-rich soils and an inflexible, top-heavy canopy structure make individuals especially prone to windthrown mortality during storms. CONCLUSIONS: Results highlight the importance of this previously unrecognised form of mortality in A. dichotoma, especially since it seems to disproportionately affect reproductively mature adult individuals in an infrequently recruiting species. Smaller, more geographically isolated and adult dominated populations in the summer rainfall zone are likely to be more vulnerable to localised extinction due to windthrow events.

Efficient protocol for rapid Aloe vera micropropagation.

CONTEXT: Aloe vera Linn. (Liliaceae) is a medicinal plant and has a number of curative properties. Vegetative propagation has not enough potential for supplying market demand. However, via in vitro propagation makes possible the mass production of Aloe plants. OBJECTIVE: The current study was conducted to investigate growth regulators' effects on proliferation of A. vera. MATERIALS AND METHODS: In this study, for comparison of plant growth regulators' effects on proliferation, the shoot tips and auxiliary buds of A. vera were cultured in the Murashige and Skoog (MS) medium. Rooted plantlets were transferred to garden soil, compost, and sand in the proportion of 1:1:1, respectively, after hardening. RESULTS: The maximum number of shoots was obtained on the medium supplemented with 1 mg/L IAA+4 mg/L BAP and 0.2 mg/L IAA+0.8 BAP mg/L. Rooting was also achieved in the same media composition proliferation of shoot. The acclimatized plants showed 100% of survival. The regenerated plants looked healthy, and they were morphologically similar to that of stock plants. CONCLUSION: These results suggest that in vitro culture may be used as a technique for rapid propagation of A. vera.

Standardization of micropropgation techniques for Aloe vera: a pharmaceutically important plant.

Aloe vera (Syn Aloe barbadensis Mill.), a medicinal plant, has a great potential in cosmetic and drug industry due to presence of more than 200 bioactive compounds. Natural propagation of Aloe vera, by means of suckers, is very slow and insufficient to meet the increasing demand of pharmaceutical and cosmetic industries. Shoot tip was used as an explant for in vitro regeneration of Aloe vera. Explants were disinfested with the use of 0.1% mercuric chloride and 0.5% sodium hypochlorite, and washed thoroughly with autoclaved distilled water. Solid MS medium was used with addition of different concentrations of 6-benzyl aminopurine and α-naphthalene acitic acid. After 7 weeks of inoculation, greatest number of shoots (11.18) and highest shoot length (12.15cm) were found in MS medium supplemented with 0.5 mg l-1 6-benzylaminopurine (BAP) along with same concentration of α-naphthalene acitic acid (NAA). Best rooting (84.67%) was found in medium supplemented with 1.5 mg l-1 of indole butyric acid (IBA). The rooted explants were then gradually acclimatized and shifted to green house.

Mass spectrometry-based metabolite profiling and antioxidant activity of Aloe vera ( Aloe barbadensis Miller) in different growth stages.

Metabolite profiling of four different-sized Aloe vera plants was performed using gas chromatography-ion trap-mass spectrometry (GC-IT-MS) and ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS) with multivariate analysis. Amino acids, sugars, and organic acids related to growth and development were identified by sizes. In particular, the relative contents of glucose, fructose, alanine, valine, and aspartic acid increased gradually as the size of the aloe increased. Anthraquinone derivatives such as 7-hydroxy-8-O-methylaloin, 7-hydroxyaloin A, and 6'-malonylnataloins A and B increased gradually, whereas chromone derivatives decreased continuously as the size of the aloe increased. The A30 aloe (size = 20-30 cm) with relatively high contents of aloins A and B, was suggested to have antioxidant components showing the highest antioxidant activity among the four different sizes of aloe. These data suggested that MS-based metabolomic approaches can illuminate metabolite changes associated with growth and development and can explain their change of antioxidant activity.

Isolation and identification of phosphate solubilizing bacteria able to enhance the growth and aloin-A biosynthesis of Aloe barbadensis Miller.

The effect of four phosphate solubilizing bacteria (PSB) was studied on growth and aloin-A content of Aloe barbadensis in soil containing tricalcium phosphate (TCP). PSB were identified based on 16S rRNA gene sequencing as Pseudomonas synxantha, Burkholderia gladioli, Enterobacter hormaechei and Serratia marcescens. These PSB solubilized 25-340 µg ml(-1) of TCP into the liquid phase. The treatment of plants with individual PSB or mixture of these increased soil available P, P uptake in plants and plant growth. The increase in aloin-A content due to higher plant biomass and unit biomass production was 673%, 294%, 276%, 119% and 108% in plants treated with a PSB consortium, P. synxantha, S. marcescens, B. gladioli, and E. hormaechei in TCP amended soil, respectively.

Assessment of genetic stability and instability of tissue culture-propagated plantlets of Aloe vera L. by RAPD and ISSR markers.

Efficient plantlet regeneration with and without intermediate callus phase was achieved for a selected genotype of Aloe vera L. which is sweet in test and used as a vegetable and source of food. Random amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) marker assays were employed to evaluate genetic stability of plantlets and validate the most reliable method for true-to-type propagation of sweet aloe, among two regeneration systems developed so far. Despite phenotypic similarities in plantlets produced through both regeneration systems, the differences in genomic constituents of plantlets produced through intermediate callus phase using soft base of inflorescence have been effectively distinguished by RAPD and ISSR markers. No polymorphism was observed in regenerants produced following direct regeneration of axillary buds, whereas 80% and 73.3% of polymorphism were observed in RAPD and ISSR, respectively, in the regenerants produced indirectly from base of the inflorescence axis via an intermediate callus phase. Overall, 86.6% of variations were observed in the plantlets produced via an intermediate callus phase. The occurrence of genetic polymorphism is associated with choice of explants and method used for plantlet regeneration. This confirms that clonal propagation of sweet aloe using axillary shoot buds can be used for commercial exploitation of the selected genotype where a high degree of fidelity is an essential prerequisite. On the other hand, a high degree of variations were observed in plantlets obtained through indirect regeneration and thus cannot be used for the mass multiplication of the genotype; however, it can be used for crop improvement through induction of somaclonal variations and genetic manipulations.

In vitro accelerated mass propagation and ex vitro evaluation of Aloe vera L. with aloin content and superoxide dismutase activity.

An innovative protocol on accelerated in vitro propagation and acclimatisation was developed in Aloe vera L. Culture was initiated with rhizomatous stem where Murashige and Skoog (MS) medium fortified with 0.5 mg L(-1) α-naphthalene acetic acid and 1.5 mg L(-1) N(6)-benzylaminopurine (BAP) promoted earliest shoot induction. Maximum shoot multiplication was achieved in MS medium supplemented with 2.5 mg L(-1)BAP. The best in vitro rooting was observed in the MS medium with 0.5 mg L(-1) indole-3-acetic acid plus 2 g L(-1) activated charcoal. The simple acclimatisation process, primarily with a combination of sand and soil (1 : 1 v/v) and finally with a blend of sand, soil and farm yard manure (2 : 1 : 1 v/v), ensured a 98% survival rate. Overall, 192 true-to-type plantlets were achieved from a single explant within 85 days. Morphologically, in vitro generated plants performed better than conventionally propagated plants; nevertheless the similarity in aloin content, gel content and superoxide dismutase activity was corroborated.

Sistema de policultivos en plantas medicinales: aloe vera, Calendula officinalis, Matricaria recutita, Plantago lanceolata y Plantago major / System of polycultures in medicinal plants: aloe vera, Calendula officinalis, Matricaria recutita, Plantago lanceolata and Plantago major

Fundamentos: existe una tendencia creciente por los agricultores a desarrollar las producciones agrícolas mediante sistemas de policultivos. Objetivos: demostrar las ventajas del sistema de policultivo sobre el monocultivo basados en el incremento del rendimiento de masa vegetal de las especies que lo integran. Métodos: en la Estación Experimental de Plantas Medicinales Dr Juan Tomás Roig se investigó sobre suelo ferralítico rojo hidratado (ferralsols), en una plantación establecida de Aloe vera (L.) N. L. Burm. cultivo perenne y principal, el intercalamiento de varias especies: Calendula officinalis L., Matricaria recutita L., Plantago lanceolata L. y Plantago major L.; cultivos de períodos vegetativos cortos para aprovechar el espacio entre surcos que requiere esta planta; se determinó el rendimiento de masa vegetal fresca en cada una de las especies de esta compleja asociación y se compararon con los de sus respectivos cultivos únicos o monocultivos. Los valores obtenidos se analizaron mediante análisis de varianza, además se calculó el incremento productivo a partir del cual se determinó el uso equivalente de la tierra. Resultados: de forma general, se encontró en todas las especies componentes del policultivo (cultivo permanente y plantas intercaladas) ventajas sobre el monocultivo en cuanto a sus rendimientos, sin afectación de los principios activos, así como el aumento de la eficiencia productiva de los suelos. Conclusiones: se demostró en las especies estudiadas la superioridad que ofrece el sistema de siembra por policultivo(AU)

Foundations: there is an increasing trend on the part of the agriculturists to develop productions by polyculture systems. Objectives: to show the advantages of the polyculture system over the monoculture based on the increase of the yield of plant mass of the species included. Methods: in an established plantation of Aloe vera (L.) N. L. Burm., perennial and main culture, with hydrated red ferriferous soil (ferralsols), at Dr Juan Tomás Roig Experimental Station of Medicinal Plants, it was investigated the intercropping of various species: Calendula officinalis L., Matricaria recutita L., Plantago lanceolata L. and Plantago major L.; cultures of short vegetative periods used to avail the space between furrows required by this plant. The yielding of fresh plant mass was also determined in each of the species of this complex association and they were compared with those of their respective unique cultures or monocultures. The values obtained were analyzed by variance analysis. The productive growth from which the equivalent use of the soil was determined was calculated, too. Results: generally, in all the species composing the polyculture (permanent culture and intercropped plants) there were advantages over the monoculture as regards their yieldings without affecting the active principles. An increase of the productive efficiency of the soils was also observed. Conclusions: the superiority of the polyculture system was proved in the studied species(AU)

Sistema de policultivos en plantas medicinales: aloe vera, Calendula officinalis, Matricaria recutita, Plantago lanceolata y Plantago major / System of polycultures in medicinal plants: aloe vera, Calendula officinalis, Matricaria recutita, Plantago lanceolata and Plantago major

Fundamentos: existe una tendencia creciente por los agricultores a desarrollar las producciones agrícolas mediante sistemas de policultivos. Objetivos: demostrar las ventajas del sistema de policultivo sobre el monocultivo basados en el incremento del rendimiento de masa vegetal de las especies que lo integran. Métodos: en la Estación Experimental de Plantas Medicinales Dr Juan Tomás Roig se investigó sobre suelo ferralítico rojo hidratado (ferralsols), en una plantación establecida de Aloe vera (L.) N. L. Burm. cultivo perenne y principal, el intercalamiento de varias especies: Calendula officinalis L., Matricaria recutita L., Plantago lanceolata L. y Plantago major L.; cultivos de períodos vegetativos cortos para aprovechar el espacio entre surcos que requiere esta planta; se determinó el rendimiento de masa vegetal fresca en cada una de las especies de esta compleja asociación y se compararon con los de sus respectivos cultivos únicos o monocultivos. Los valores obtenidos se analizaron mediante análisis de varianza, además se calculó el incremento productivo a partir del cual se determinó el uso equivalente de la tierra. Resultados: de forma general, se encontró en todas las especies componentes del policultivo (cultivo permanente y plantas intercaladas) ventajas sobre el monocultivo en cuanto a sus rendimientos, sin afectación de los principios activos, así como el aumento de la eficiencia productiva de los suelos. Conclusiones: se demostró en las especies estudiadas la superioridad que ofrece el sistema de siembra por policultivo.

Foundations: there is an increasing trend on the part of the agriculturists to develop productions by polyculture systems. Objectives: to show the advantages of the polyculture system over the monoculture based on the increase of the yield of plant mass of the species included. Methods: in an established plantation of Aloe vera (L.) N. L. Burm., perennial and main culture, with hydrated red ferriferous soil (ferralsols), at Dr Juan Tomás Roig Experimental Station of Medicinal Plants, it was investigated the intercropping of various species: Calendula officinalis L., Matricaria recutita L., Plantago lanceolata L. and Plantago major L.; cultures of short vegetative periods used to avail the space between furrows required by this plant. The yielding of fresh plant mass was also determined in each of the species of this complex association and they were compared with those of their respective unique cultures or monocultures. The values obtained were analyzed by variance analysis. The productive growth from which the equivalent use of the soil was determined was calculated, too. Results: generally, in all the species composing the polyculture (permanent culture and intercropped plants) there were advantages over the monoculture as regards their yieldings without affecting the active principles. An increase of the productive efficiency of the soils was also observed. Conclusions: the superiority of the polyculture system was proved in the studied species.

Micropropagation of endangered plant species.

This chapter describes the multiple-shoot-based methods of micropropagation for endangered plant species. Taxus and aloe are used here as examples. For Taxus, the process of micropropagation includes initiating multiple shoots, elongating shoots, rooting shoots, and transplanting plantlets. For aloe, the process of micropropagation includes initiating multiple shoots, rooting shoots, and transplanting plantlets.

Silicate improves growth and ion absorption and distribution in aloe vera under salt stress.

Si 2.0 mmol/L in irrigation solution alleviated significantly the inhibition of NaCl stress of 100 or 200 mmol/L to aloe growth. Exogenously applied Si decreased significantly Na(+) and Cl(-) contents, increased K(+) content and K(+)/Na(+) ratio and selectivity ratio of absorption (AS(K, Na)) and of translocation (TS(K, Na)) to K(+) and Na(+) in aloe plant under both NaCl 100 and 200 mmol/L stresses for 30 d. In this way, the ion homeostasis in aloe plant under NaCl stress was maintained, as was proved by X-ray microanalysis of root tip and leaf across sections. One of the mechanisms to achieve this may be the significant enhancement of H(+)-ATPase activities by the addition of silicate in plasma membrane and tonoplast, H(+)-pyrophosphatase (H(+)-PPase) activity in tonoplast isolated from aloe root tips under NaCl stress.

Effect of ultrasonic exposure on Ca2+-ATPase activity in plasma membrane from Aloe arborescens callus cells.

We investigated the effect of ultrasound on plasma membrane (PM) Ca2+-ATPase activity of Aloe arborescens callus cells in solid culture. The calluses were exposed by a 20 kHz digital sonifier at the powers of 2 and 10 W from the effective exposure times of 2-10 s. PM Ca2+-ATPase activity was almost significantly higher at 2 W both in continuous wave and 10% duty cycle than that of the control (no ultrasound) at effective exposure times of 5 and 10 s. However, its activity decreased at 10 W in continuous wave exposure. It is possible that the PM Ca2+-ATPase configuration or structure may be partly damaged by high-energy ultrasound at 10 W. Our results showed that low-energy ultrasound exposure was a useful physical field to stimulate A. arborescens callus cells to adapt environmental stress through PM Ca2+-ATPase activity increase.

Efectos estimulantes del crecimiento de extractos acuosos de plantas medicinales y gel de Aloe vera (L.) N. L. Burm / Stimulating efffects of the growth of aqueous extracts of medicinal plants and Aloe vera (L.) N. L. Burm. gel

El presente estudio se realizó con el montaje de 6 experimentos, (replicados 3 veces cada uno), en el laboratorio de Cultivo de Tejidos de la Estación Experimental de Plantas Medicinales "Dr. Juan Tomás Roig". Cada experimento correspondió a una especie determinada. Se utilizó un diseño experimental completamente aleatorizado, con 10 tratamientos y 10 repeticiones. Los tratamientos empleados correspondieron a cada uno de los extractos de las plantas medicinales estudiadas y gel de Aloe vera (L.) N. L. Burm. y un tratamiento control que utiliza reguladores de crecimiento sintéticos, para la brotación y enraizamiento. Cada repetición consistió en un tubo de ensayo con el medio nutritivo adecuado para cada especie, donde se sembró un explante por cada tubo. Se encontraron efectos estimulantes del crecimiento en los extractos estudiados y correspondió al gel de A. vera el mejor comportamiento, superior a los reguladores usados tradicionalmente, en la formación de raíces. Este hecho demostró la posible presencia de actividad auxínica en el mismo. El extracto de sauce (Salix humboldtiana Wild), tuvo también un comportamiento satisfactorio en este aspecto, lo que corroboró resultados anteriormente obtenidos. Sin embargo, ambos extractos no mostraron indicios importantes de contar con actividad citoquinínica. En este caso, los extractos de Plantago lanceolata L. y Plantago major L. tuvieron un mejor comportamiento(AU)

Evaluation of antioxidant potential of aloe vera (Aloe barbadensis miller) extracts.

The polysaccharide and flavonoid concentrations of two-, three-, and four-year-old Aloe vera were determined, and their antioxidant activities were evaluated compared to BHT and alpha-tocopherol by the DPPH radical scavenging method and the linoleic acid system at 100 microg of soluble solids per mL of ethanol. The results showed that three-year-old Aloe vera contained significantly higher levels of polysaccharides and flavonoids than two- and four-year-old Aloe vera, and no significant differences in flavonoid levels were found between three- and four-year-old Aloe vera. All the aloe extracts showed significant antioxidant activity. The antioxidant activity of Aloe vera extracts and reference compounds followed the order: three-year-old Aloe vera > BHT > four-year-old Aloe vera > alpha-tocopherol > two-year-old Aloe vera. The three-year-old extract exhibited the strongest radical scavenging activity of 72.19%, which is significantly higher than that of BHT at 70.52% and alpha-tocopherol at 65.20%. These data suggest that the growth stage plays a vital role in the composition and antioxidant activity of Aloe vera.

[Study on application of arbuscular-mycorrhizas in growing seedings of Aloe vera].

Tissue culture seedlings of Aloe vera L. inoculated with 7 AMF(arbuscular mycorrhiza fungi) in a greenhouse in Guangzhou showed that the percentage of infection was 99.67%-100%, the index of infected was 73.3%-86.67%. After being inoculated 13 months, the seedling high raised 19.88%-51.91%, the leaves length raised 13.13%-150.96%. After being inoculated 15 months, the leaves juice of Aloe vera raised 60.87%-233.8% and the dried of leaves juice raised 217%-724%.